1. Field of Invention
This disclosure relates to a liquid crystal polyester resin composition and a printed circuit board that uses the composition. This disclosure also relates to a liquid crystal polyester resin composition with improved thermal stability which comprises a liquid crystal polyester, a polybenzimidazole and an aprotic solvent, and a printed circuit board that uses the composition.
2. Description of the Related Art
Recent advances in information and communication technologies have rapidly transformed our society into a high-tech communication and information society. The trend toward miniaturization and high performance of electronic devices (e.g., mobile phones and personal computers) has led to high-density integration of printed circuit boards as essential elements of electronic devices. Such high-density integration is achieved through layering of printed circuit boards, the reduction in the thickness of printed circuit boards, the reduction in the diameter and interval of through-holes, and so on. Under these circumstances, there is a need for substrate materials that exhibit improved performance characteristics.
The use of high operating frequencies for rapid processing of data in electronic digital devices (e.g., computers) involves the problems of transmission loss and signal delay. For example, FR-4 copper clad laminate, which is presently the most widely used type of copper clad laminate, suffers from problems of increased transmission loss and signal delay because of its relatively high permittivity (ca. 3.5-5.5). A signal delay in a printed circuit board increases linearly with the square root of the relative permittivity of an insulating material that is disposed around the lines. Thus, a low-permittivity material having a low dielectric loss is needed to produce a substrate where a high transmission rate is required. There is also a need for a substrate material that is thermally stable enough to withstand heat generated from the resistance of conductors.